Having doubts about my bf

I’ve been with my bd/bf on and off for 4 yrs. In the beginning of our relationship he treated me like absolute dog shit. Lied manipulated made me feel ugly while pregnant and after, wasn’t there for my sons birth. Etc.

I had no self worth so I stayed with him. He finally got better within the past year and a half. Treats me like a queen. A part of me thinks it’s cause I look better now than what I did. Anyways, I’m happier.

Now proposing has been getting brought up. Of course at first I was excited, but the more I think bout it, the more disgusted I am that I stayed with him. I am so much more confident and know my worth. So now that I see it and see how bad he really did me. Idk what I want to do. Love him, but other part of me hates him and wants to separate. Any advice ?